Exhaust gas aftertreatment bypass system and methods

ABSTRACT

A method for protecting an exhaust aftertreatment system of an internal combustion engine from deterioration by selectively diverting exhaust gasses from the engine away from a component of the exhaust aftertreatment system includes assessing a status of an operating condition associated with a physical condition of the component of the internal combustion engine. The status of the operating condition is compared with a threshold value that corresponds with deterioration of the physical condition of the component. A valve upstream of the component is moved to a first position to open a bypass fluid path directing exhaust gasses around the component when the status of the operating condition meets the threshold value to reduce deterioration of the component. The valve is moved to a second position to close the bypass fluid path thereby directing exhaust gasses to the component when the status of the operating condition does not meet the threshold.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.13/789,345, entitled “Exhaust Gas Aftertreatment Bypass System andMethods,” filed Mar. 7, 2013, the disclosure of which is herebyincorporated herein by reference in its entirety.

FIELD

This disclosure relates generally to exhaust aftertreatment systems forinternal combustion engines, and more particularly to a bypass systemand method for protecting exhaust aftertreatment devices from harmfulenvironmental or operating conditions.

BACKGROUND

Exhaust aftertreatment systems include components used to processexhaust gasses produced by an internal combustion engine for the purposeof reducing harmful exhaust emissions. Some aftertreatment systemcomponents, such as diesel oxidation catalysts (DOC) and selectivecatalytic reduction (SCR) catalysts, use catalytic materials tochemically convert potentially harmful exhaust emissions into other lessharmful emission products. Such catalyst-based exhaust aftertreatmentsystem components are desirable for their ability to efficiently controlemissions. Unfortunately, some catalyst-based exhaust aftertreatmentsystem components are also susceptible to damage from adverseoperational and environmental conditions

For example, many components have an acceptable operating temperaturerange. Exceeding the upper limits of the temperature range can result inrelease of undesirable oxides, such as pentoxide being released from aVanadium-based catalyst. On the other hand, operating at temperaturesbelow the lower limits of the temperature range can result in unburnedhydrocarbon being trapped or absorbed in the catalyst. Significantquantities of unburned hydrocarbon can become combustible, and pose athreat to aftertreatment hardware and the environment, due touncontrolled thermal events

Another potential hazard to catalyst-based exhaust aftertreatment systemcomponents is the use of high sulfur-content fuels. Many of thecatalysts used in exhaust aftertreatment systems include catalyticmaterials capable of oxidizing sulfur. Consequently, due to sulfurpoisoning, fuels having high sulfur content can overwhelm and deactivatea catalyst configured to oxidize other emissions components.

Engine failures are yet another hazard to the components of exhaustaftertreatment systems. A bearing seal failure, for instance, mightrelease oil into the exhaust line that could damage the components of anexhaust aftertreatment system.

SUMMARY

The subject matter of the present application has been developed inresponse to the present state of the art, and in particular, in responseto the problems and needs in exhaust aftertreatment art that have notyet been fully solved by currently available exhaust aftertreatmentsystems. For example, the inventors of the subject matter of the presentapplication have recognized that, given the high costs of exhaustaftertreatment systems, it would be advantageous to have a bypass systemthat would protect the aftertreatment components from operational andenvironmental hazards that might cause damage to the components.Additionally, the inventors of the subject matter of the presentapplication have recognized that a control system and methodology forbypassing one or more components of an exhaust aftertreatment systemwould extend the service life of the components when operational orenvironmental hazards threaten the components.

Accordingly, in one embodiment, the subject matter of the presentapplication has been developed to provide a method for protecting anexhaust aftertreatment system of an internal combustion engine fromdeterioration by selectively diverting exhaust gasses from the engineaway from a component of the exhaust aftertreatment system. The methodincludes assessing a status of an operating condition associated with aphysical condition of the component of the internal combustion engine.The status of the operating condition is compared with a threshold valuethat corresponds with deterioration of the physical condition of thecomponent. A valve upstream of the component is moved to a firstposition to open a bypass fluid path directing exhaust gasses around thecomponent when the status of the operating condition meets the thresholdvalue to reduce deterioration of the component. The valve is moved to asecond position to close the bypass fluid path thereby directing exhaustgasses to the component when the status of the operating condition doesnot meet the threshold value.

In one implementation of the method, assessing the status of theoperating condition includes assessing a temperature of the exhaustgasses and comparing the temperature to a lower temperature thresholdvalue below which the exhaust gasses include a predetermined level ofunburned hydrocarbons.

In another implementation, assessing the status of the operatingcondition includes assessing a temperature of the exhaust gasses andcomparing the temperature to an upper temperature threshold value abovewhich the component degrades and produces harmful byproducts, such aspentoxide.

In another implementation of the method, assessing the status of theoperating condition includes assessing a geographical location of theinternal combustion engine and comparing the geographical location to athreshold value includes comparing the geographical location of theengine to geographical locations that do not require emissions controlsfor internal combustion engines.

In yet another implementation of the method, assessing the status of theoperating condition includes assessing a chemical formulation of fuelused by the internal combustion engine and comparing fuel chemistry to athreshold value includes comparing the fuel chemistry to chemicals thatdeteriorate the component, such as sulfur.

The step of moving the valve to the first position based on thethreshold comparison can also be overridden by a user by manually movingthe valve to the second position to close the first fluid path and openthe second fluid path to bypass the exhaust aftertreatment device.

Additionally, according to another embodiment, the subject matter of thepresent application has been developed to provide an apparatus forbypassing an exhaust aftertreatment device of an internal combustionengine to protect a selective catalytic reducer or reduction (SCR)component of the exhaust aftertreatment device from deterioration. Theapparatus includes a flow control valve operable to open and close abypass fluid path wherein exhaust gasses from the engine bypass theexhaust after treatment device when the valve is in the open positionand the exhaust gasses flow through the exhaust aftertreatment devicewhen the valve is in the closed position. A sampling module samples anoperating condition of the internal combustion engine that is associatedwith a physical condition of the SCR component. A comparison modulecompares the operating condition with a threshold value that correspondswith deterioration of the physical condition of the SCR component. Acontrol module operates the flow control valve to open the bypass fluidpath if the operating condition does not meet the threshold conditionand to close the bypass fluid path if the operating condition meets thethreshold condition.

In one implementation of the apparatus a user interface is associatedwith the control module. The user interface is configured to accept userinput to override the control module control of the flow control valveand manually open the valve to the bypass fluid path to bypass theexhaust aftertreatment device.

In one embodiment of an internal combustion engine, the engine includesan exhaust aftertreatment system including a SCR component in exhaustreceiving communication with the internal combustion engine. A bypasssystem is operatively associated with the exhaust aftertreatment systemand operates to bypass the SCR component when an operating condition ofthe internal combustion engine that corresponds with deterioration of aphysical condition of the SCR component is detected.

In one implementation, the bypass system includes a flow control valveoperable to open and close a bypass fluid path with exhaust gasses fromthe engine bypassing the exhaust after treatment device when the valveis in the open position and the exhaust gasses flow through the exhaustaftertreatment device when the valve is in the closed position. Thebypass system also includes a controller that determines whether theflow control valve is open to the bypass fluid path by sampling theoperating condition of the internal combustion engine that is associatedwith the physical condition of the SCR component. The controllercompares the sampling of the operating condition with a threshold valuethat corresponds with deterioration of the physical condition of the SCRcomponent.

The described features, structures, advantages, and/or characteristicsof the subject matter of the present disclosure may be combined in anysuitable manner in one or more embodiments and/or implementations. Inthe following description, numerous specific details are provided toimpart a thorough understanding of embodiments of the subject matter ofthe present disclosure. One skilled in the relevant art will recognizethat the subject matter of the present disclosure may be practicedwithout one or more of the specific features, details, components,materials, and/or methods of a particular embodiment or implementation.In other instances, additional features and advantages may be recognizedin certain embodiments and/or implementations that may not be present inall embodiments or implementations. Further, in some instances,well-known structures, materials, or operations are not shown ordescribed in detail to avoid obscuring aspects of the subject matter ofthe present disclosure. The features and advantages of the subjectmatter of the present disclosure will become more fully apparent fromthe following description and appended claims, or may be learned by thepractice of the subject matter as set forth hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the advantages of the subject matter may be more readilyunderstood, a more particular description of the subject matter brieflydescribed above will be rendered by reference to specific embodimentsthat are illustrated in the appended drawings. Understanding that thesedrawings depict only typical embodiments of the subject matter and arenot therefore to be considered to be limiting of its scope, the subjectmatter will be described and explained with additional specificity anddetail through the use of the drawings, in which:

FIG. 1 is schematic representation of an internal combustion engineaccording to one embodiment of the present invention shown with anexhaust aftertreatment bypass system coupled to an exhaust system of theengine;

FIG. 2 is a schematic representation of an exhaust aftertreatment bypasssystem according to one embodiment of the present application, shownwith a flow control valve directing flow into a first fluid flowpathway;

FIG. 3 is a schematic representation of the bypass system of FIG. 1shown with the flow control valve directing flow into a second fluidflow pathway;

FIG. 4 is a schematic block diagram of a controller of the engine systemof FIG. 1 in accordance with one representative embodiment;

FIG. 5 is a schematic representation of an exhaust aftertreatment bypasssystem according to another embodiment shown with a flow control valvedirecting flow into a first fluid flow pathway;

FIG. 6 is a schematic representation of the bypass system of FIG. 3shown with the flow control valve directing flow into a second fluidflow pathway;

FIG. 7 is a schematic representation of an exhaust aftertreatment bypasssystem according to another embodiment shown with a flow control valvedirecting flow into a first fluid flow pathway;

FIG. 8 is a schematic representation of the bypass device of FIG. 5shown with the flow control valve directing flow to a second fluid flowpathway; and

FIG. 9 is a flow chart of a method for protecting an exhaustaftertreatment device of an internal combustion engine system using abypass device in accordance with another embodiment of the presentapplication.

DETAILED DESCRIPTION

Reference throughout this specification to “one embodiment,” “anembodiment,” or similar language means that a particular feature,structure, or characteristic described in connection with the embodimentis included in at least one embodiment of the present disclosure.Appearances of the phrases “in one embodiment,” “in an embodiment,” andsimilar language throughout this specification may, but do notnecessarily, all refer to the same embodiment. Similarly, the use of theterm “implementation” means an implementation having a particularfeature, structure, or characteristic described in connection with oneor more embodiments of the present disclosure, however, absent anexpress correlation to indicate otherwise, an implementation may beassociated with one or more embodiments.

Referring to FIG. 1, according to one embodiment, an internal combustionengine 10 is shown with a bypass system 100 operatively associated withan exhaust aftertreatment system 20 that is in exhaust receivingcommunication with an exhaust manifold 12 of the internal combustionengine. The bypass system 100 is configured to protect an exhaustaftertreatment component 22 from potentially harmful operational andenvironmental conditions.

Generally, the bypass system 100 forms part of the exhaustaftertreatment system 20, which is configured to reduce harmfulemissions in exhaust gasses generated by the internal combustion engine10. The exhaust aftertreatment system 20 includes one or more components(e.g., the exhaust aftertreatment component 22) configured to treat theexhaust gas in a particular way. The exhaust aftertreatment system 20also includes a main exhaust line 24 that provides exhaust gas to theone or more components prior to being treated and directs exhaust gasaway from the one or more components after being treated. Accordingly,the main exhaust line 24 includes an upstream section 26 (e.g., upstreamof the components) and a downstream section 28 (e.g., downstream of thecomponents).

The components 22 that treat the exhaust gas include a catalyst basedtreatment device that has a finite useful life based on a catalyticchemical reaction with the exhaust gasses that remove undesirableemissions from the exhaust gasses. Thus, the more exposure the component22 has to exhaust gasses, the more the component will deteriorate andthe shorter the component's useful life will be. For this reason, it isdesirable to control exposure of the catalyst component 22 to theexhaust gasses to maximize the useful life of the component. In theembodiments described herein, the component 22 can include a selectivecatalytic reducer (SCR), a selective catalytic reducer coated filter, adiesel oxidation catalyst (DOC), a diesel particulate filter (DPF) witha selective catalytic reducer, and the like.

Hence, to protect the component 22 from unnecessary exposure to theexhaust gasses, the bypass system 100 includes a bypass line 110 with aninlet 112 fluidly coupleable to the upstream section 26 of the mainexhaust line 24 and an outlet 114 fluidly coupleable to the downstreamsection 28 of the main exhaust line. The bypass system 100 also includesa flow control valve 120 that is operable to divert exhaust gas flowaround the exhaust aftertreatment component 22 via the bypass line 110.

Referring to FIGS. 2 and 3, the bypass system 100 is shown with the flowcontrol valve 120 disposed in the upstream section 26 of the mainexhaust line 24 proximate the inlet 112 to the bypass line 110. The flowcontrol valve 120 is actuatable between at least first and secondpositions. As shown in FIG. 2, in the first position (e.g., closedposition), the flow control valve 120 defines a first fluid pathwayextending from the upstream section 26 of the main exhaust line 24,through the flow control valve 120, and into the aftertreatmentcomponent 22. In other words, the flow control valve 120 in the closedposition fluidly couples the upstream section 26 of the main exhaustline 24 with the aftertreatment component 22 such that exhaust gas,indicated by directional arrow 32, flows from the upstream section 26into the aftertreatment component 22.

In contrast, as shown in FIG. 3, in the second position (e.g., openposition), the flow control valve 120 at least partially blocks thefirst fluid pathway 32 to the aftertreatment component 22 and defines asecond fluid pathway extending from the upstream section 26 of the mainexhaust line 24, through the flow control valve 120, around theaftertreatment component 22, and into the downstream section 28 of themain exhaust line. In other words, the flow control valve 120 in theopen position fluidly couples the upstream section 26 with thedownstream section 28 while bypassing the component 22 such that exhaustgas, indicated by directional arrow 34, flows from the upstream section26 directly into the downstream section 28. Although not shown, thedownstream section 28 of the main exhaust line may be coupled to atailpipe of the aftertreatment system.

The flow control valve 120 can be a gate valve 122, a ball valve, acheck valve a globe valve, a butterfly valve or other similar type valveconfigured to direct the flow of gas based fluids as known in the art.Additionally, the flow control valve 120 can have an actuator 124 thatcan move the valve between the first position and the second position.The actuator 124 can receive power from an electronic, pneumatic, orvacuum source.

A controller 130 may be designed to provide a performance status to anon-board diagnostic system 150, or OBD 150. The OBD 150 may convey thestatus to a user such as a driver of the vehicle containing the enginesystem 10 (FIG. 1), for example, with a light or LED, an auditory signalor alarm, an analog gauge, a digital readout, or the like. In theembodiment shown in FIGS. 2 and 3, the controller 130 is in electroniccommunication with the flow control valve 120 to control movement of theflow control valve 120 between the first position and the secondposition.

Referring to FIG. 4, the controller 130 may include various modules forcontrolling the operation of the exhaust aftertreatment system 20. Forexample, the controller 130 may include one or more modules forcontrolling the operation of the bypass system 100. As embodied in FIGS.2 and 3, the controller 130 includes a sampling module 132, a comparisonmodule 134, and a control module 136. The control module 136 may controlthe ordinary operation of the bypass system 100 and the moreparticularly the flow control valve 120 by providing instruction to movethe valve to either the first position (e.g., closed position) 138 orthe second position (e.g., open position) 140.

The sampling module 132 may, at desired times, sample an operatingcondition of the internal combustion engine and the aftertreatmentcomponent 22 that is associated with a physical condition of thecomponent 22. The sampling module can be a physical sensor 52 (FIGS. 2and 3), such as a thermocouple, a virtual sensor, and the like. Thesampling module 132 sends data regarding the sampled condition to thecomparison module 134 for analysis.

The comparison module 134 may include a processor with logic andinstructions for comparing data from the sampling module 132 with athreshold value of the operating condition being sampled. When the datafrom the sampling module 132 exceeds the threshold value, the comparisonmodule 134 informs the control module 136 which sends instructions 140to the bypass system 100 to move the valve 120 to the second position tobypass the aftertreatment component 22. When the data from the samplingmodule 132 meets the threshold value, the comparison module 134 informsthe control module 136 which sends instructions 138 to the bypass system100 to move the flow control valve 120 to the first position to allowthe exhaust gasses to flow through the aftertreatment component 22.

The controller 130 and its various modular components may compriseprocessor, memory, and interface modules that may be fabricated ofsemiconductor gates on one or more semiconductor substrates. Eachsemiconductor substrate may be packaged in one or more semiconductordevices mounted on circuit cards. Connections between the modules may bethrough semiconductor metal layers, substrate-to-substrate wiring, orcircuit card traces or wires connecting the semiconductor devices.

While not specifically illustrated and described with reference to FIG.4, the controller 130 can include additional modules for conductingother control system functions. For example, the controller can includea calculation module 142 and a reporting module 144. The reportingmodule 144 can report the performance status of the various modules inthe controller 130 to a user via an output device 146.

Additionally, the sampling module 132 can receive data from multiplesources such as additional sensors 148 that sample other operatingconditions of the internal combustion engine that can have adeteriorating effect on the aftertreatment component 22. For example,the additional sensors 148 can sample an upper temperature of theexhaust gasses, a lower temperature of the exhaust gasses, a sulfurcontent of the fuel and exhaust gasses, and a global positioning sensor(GPS) location of the engine during operation as described below.

Although not shown in the Figures, other sensors (e.g. OBDII sensors)located throughout the engine can be used to detect engine performanceproblems that may adversely affect the SCR device, such as a bearingseal failure that releases engine oil into the exhaust system and theaftertreatment system. In such cases, the controller can receive datafrom the engine sensors and turn the exhaust stream to the bypasspathway in order to prevent damage to the catalyst due to the engineperformance problems.

Returning to FIG. 4, it will be appreciated that since the exhaustgasses pass through and are treated by the exhaust aftertreatment device20, the physical properties of the exhaust gasses can have adeteriorating effect on the exhaust aftertreatment component 22 that canshorten the service life of the aftertreatment component. For example,in catalyst based exhaust aftertreatment devices such as SCR devices andSCR coated filters, temperature of the exhaust gasses can result inundesirable and even dangerous operating conditions for the SCR. If thetemperature of the exhaust gasses is too high, the catalyst in the SCRdevice can produce undesirable oxides, such as pentoxide from a vanadiabased catalyst, which are produced at an unacceptable rate attemperatures of around 550 degrees C. Moreover, if the temperatureexceeds an even higher threshold, a vanadia based catalyst may berendered useless. Other materials used as catalysts in SCR devices, asknown in the art, may also degrade, produce harmful byproducts, or berendered useless at relatively high temperatures.

Consequently, the controller 132 includes a sensor 52, real or virtual,that samples an upper temperature of the exhaust gasses and a samplingmodule 132 that receives the sensor data. The sampling module 132 sendsthe sampled temperature data to the comparison module 134 where the datais compared to a high temperature threshold. In one aspect, the hightemperature threshold is set at a temperature that is below thetemperature (e.g., 550 degrees C.) at which harmful byproducts, such aspentoxides, may be produced at an unacceptable rate. In another aspect,the high temperature threshold is set at a temperature that is below thetemperature at which the catalyst is rendered useless by overheating.The comparison module 134 sends the comparison results to the controlmodule 136 to move the flow control valve 120 to the second position tobypass the exhaust aftertreatment device 20 if the temperature exceedsthe high temperature threshold, thereby protecting the aftertreatmentcomponent 22 from an undesirable production of harmful byproducts, suchas pentoxides, or damage from heat that may render the catalyst useless.

On the other hand, if the exhaust gas temperatures are too low, theexhaust gasses may contain an unacceptably high amount of unburnedhydrocarbons. Large quantities of unburned hydrocarbons can overwhelmthe catalyst such that the catalyst leaves residual unburnedhydrocarbons in the exhaust aftertreatment device 20. Unburnedhydrocarbons affect the efficiency of the catalyst and can create anundesirable thermal event if enough accumulate within the aftertreatmentdevice 20. Therefore, a high unburned hydrocarbon rate in the exhaustgas can result in a high unburned hydrocarbon adsorption rate on theaftertreatment device 20. However, the unburned hydrocarbon productionrate may be, but is not necessarily, equal to or proportional to theunburned hydrocarbon device adsorption rate. Accordingly, in someimplementations, the sensed or estimated rate of accumulation oradsorption of unburned hydrocarbons on the device 20 relative to athreshold can be another factor controlling the operation of the exhaustbypass valve.

Accordingly, the controller 130 includes a virtual or physical sensor 52to detect a low temperature of the exhaust gasses which would indicatethe presence of unburned hydrocarbons, a virtual or physical sensor thatsamples for unburned hydrocarbon, a virtual or physical sensor thatsamples for both low temperature and for unburned hydrocarbons, or avirtual or physical that determines an accumulation or adsorption rateof unburned hydrocarbons on a catalyst or other aftertreatment device.The controller also includes a sampling module 132 that receives thedata from the sensor. The sampling module 132 sends the sampledtemperature or unburned hydrocarbon data to the comparison module 134where the data is compared to a low temperature threshold or an unburnedhydrocarbon threshold respectively. In one aspect, the low temperaturethreshold is set at temperature at which hydrocarbons are known toaccumulate in the exhaust aftertreatment devices at an unacceptablerate. In another aspect the unburned hydrocarbon threshold is set at alevel at which unburned hydrocarbons are known to interfere with thecatalyst material in the SCR. The comparison module 134 sends thecomparison results to the control module 136 to move the flow controlvalve 120 to the second position to bypass the exhaust aftertreatmentdevice 20 if the temperature falls below the low temperature thresholdor the unburned hydrocarbon rate exceeds the unburned hydrocarbonthreshold level, thereby protecting the aftertreatment component 22 froman undesirable buildup of unburned hydrocarbons.

Another physical property of the exhaust gasses that can have adeteriorating effect on the exhaust aftertreatment component 22 is thepresence of sulfur in the exhaust gasses. Some petroleum based fuelshave a high sulfur content. Unfortunately, exhaust from high sulfurcontent fuels is also high in sulfur. Sulfur is also oxidized bycatalyst based exhaust aftertreatment devices and can overwhelm thecatalyst causing “sulfur poisoning” of the catalyst wherein the catalystis rendered useless.

Therefore, the controller 130 includes a sensor 148 that samples thesulfur content of the exhaust gasses or the fuel and a sampling module132 that receives the sensor data. The sampling module 132 sends thesampled sulfur content data to the comparison module 134 where the datais compared to a sulfur content threshold value. The comparison module134 sends the comparison results to the control module 136 to move theflow control valve 120 to the second position to bypass the exhaustaftertreatment device 20 if the sulfur content is above the sulfurcontent threshold, thereby protecting the aftertreatment component 22from an undesirable buildup of sulfur within the aftertreatment device.

Yet another operating parameter that can have a deteriorating effect onthe exhaust aftertreatment component 22 is operation of the exhaustaftertreatment device when control of emissions is not needed. Forexample, some geographical areas of the world do not have emissionsregulations and being able to bypass the exhaust aftertreatment device20 when traveling in these areas can extend the service life of theaftertreatment device.

Hence, the controller 130 includes a sensor 148 that samples thegeographic location of the internal combustion engine from a globalpositioning sensor (GPS). The sampling module 132 sends the GPS data tothe comparison module 134 where the data is compared to a GPS thresholdvalue. The comparison module 134 sends the comparison results to thecontrol module 136 to move the flow control valve 120. If the GPSlocation is found within a geographical area that requires exhaustemission controls, then the control module 136 sends a signal to theactuator 124 to move or maintain the flow control valve 120 in the firstposition opening the first fluid path 32 which directs flow through theafter treatment device 20. If the GPS location is in a geographical areathat does not require exhaust emissions control, the control module 136sends a signal to move the flow control valve 120 to the second positiondirecting flow to the second flow path that bypasses the exhaustaftertreatment device 20.

The flow control valve 120 can also be manually opened or closed therebyoverriding the controller 130. In one implementation, the actuator 124on the flow control valve can be manually adjusted to override thecontroller 130 and move the flow control valve 120 between the firstposition and the second position. In another implementation, thecontroller 130 can receive input data directly from a user through auser interface 56 (FIGS. 2 and 3). The user interface 56 can be aphysical interface, such as a keypad, or a virtual interface, as knownin the art. Through the user interface 56, the user can override thecontroller 130 and direct the controller 130 to move the flow controlvalve 120 to the first or second position as desired. In either case,the bypass system 100 described herein provides a bypass pathway 110that can be selectively opened or closed by the user in order to protectand preserve the life of the exhaust aftertreatment component 22.

Referring to FIGS. 5 and 6, a bypass system, indicated generally at 300,is shown in accordance with another embodiment for use in protecting anexhaust aftertreatment system 220 that is in exhaust receivingcommunication with an exhaust manifold of an internal combustion engine(not shown). The bypass system is similar in many respects to the bypasssystem 100 described above and shown in FIGS. 1-4. The bypass system 300is configured to protect the exhaust aftertreatment component 22 frompotentially harmful operational and environmental conditions.

The bypass system 300 forms part of the exhaust aftertreatment system220. The exhaust aftertreatment system 220 includes one or morecomponents (e.g. the exhaust aftertreatment component 22) configured totreat the exhaust gas in a particular way. The components 22 that treatthe exhaust gas include a catalyst based treatment device, such as anSCR, SCR coated filter, and the like, that have a finite useful lifebased on a catalytic chemical reaction with the exhaust gasses thatremove undesirable emissions from the exhaust gasses.

Accordingly, to protect the component 22 from unnecessary exposure tothe exhaust gasses, the bypass system 300 includes a housing 302 with aninlet 304 and an outlet 306. The aftertreatment component 22 is disposedwithin the housing 302 and is configured to receive exhaust gasses fromthe inlet 304 and to direct treated gasses to the outlet 306.

A partition 308 is disposed within the housing 302 and separates thehousing into an inlet side 310 and an outlet side 312. The partition 308restricts flow from the inlet side 310 to the outlet side 312 such thatflow of exhaust gasses passes through the aftertreatment component 22and to the outlet 306.

A flow control valve 320 is disposed in the housing 302 adjacent theinlet 304 upstream from the aftertreatment component 22. The flowcontrol valve 320 is actuatable between at least first and secondpositions. As shown in FIG. 5, in the first position (e.g. closedposition) the flow control valve 320 defines a first fluid pathwayextending from the inlet, through the flow control valve and into theaftertreatment component 22. In other words, when the flow control valve320 is in the closed position, exhaust gasses, indicated by directionalarrow 332, flow through the valve 320 to the inlet side 310 of thehousing 302, and into the aftertreatment component 22.

In contrast, as shown in FIG. 6, in the second position (e.g. openposition) the flow control valve 320 at least partially blocks the firstfluid pathway 332 to the aftertreatment component 22 and defines asecond fluid pathway extending from the inlet side 304 of the housing302, around the aftertreatment component 22, and into the outlet side306 of the housing 302. In other words, the flow control valve 320 inthe open position fluidly couples the inlet side 304 of the housing 302with the outlet side 306 of the housing 302 while bypassing thecomponent 22 such that exhaust gas, indicated by directional arrow 334,flows through the housing 302 without flowing through the aftertreatmentcomponent 22.

The bypass system 300 also includes the controller 130 described aboveand shown in detail in FIG. 4. The controller 130 is electronicallycoupled to the flow control valve 320 to control movement of the flowcontrol valve 320 between the first position and the second position. Inthe embodiment shown in FIGS. 5 and 6, the controller sends a signal tothe actuator 124 to move the flow control valve 320 to the desiredposition.

Referring to FIGS. 7 and 8, a bypass system, indicated generally at 500,is shown in accordance with another embodiment for use in protecting anexhaust aftertreatment system 220 that is in exhaust receivingcommunication with an exhaust manifold of an internal combustion engine(not shown). The bypass system is similar in many respects to the bypasssystems 100 and 300 described above and shown in FIGS. 1-6. The bypasssystem 500 is configured to protect the exhaust aftertreatment component22 from potentially harmful operational and environmental conditions.

The bypass system 500 forms part of the exhaust aftertreatment system220. The exhaust aftertreatment system 220 includes one or morecomponents (e.g. the exhaust aftertreatment component 22) configured totreat the exhaust gas in a particular way. The components 22 that treatthe exhaust gas include a catalyst based treatment device, such as anSCR, SCR coated filter, and the like, that have a finite useful lifebased on a catalytic chemical reaction with the exhaust gasses thatremove undesirable emissions from the exhaust gasses.

Accordingly, to protect the component 22 from unnecessary exposure tothe exhaust gasses, the bypass system 500 includes a housing 502 with aninlet 504, a bypass outlet 506 and an aftertreatment outlet 508. Theaftertreatment component 22 is disposed within the housing 502 and isconfigured to receive exhaust gasses from the inlet 504 and to directtreated gasses to the aftertreatment outlet 508.

A partition 510 is disposed within the housing 502 and separates thehousing into an inlet side 512 and an outlet side 514. The partition 510restricts flow from the inlet side 512 to the outlet side 514 such thatflow of exhaust gasses passes through the aftertreatment component 22 tothe aftertreatment outlet 508 when the bypass outlet 506 is closed bythe flow control valve 520.

The flow control valve 520 is disposed in the housing 502 adjacent thebypass outlet 506 upstream from the aftertreatment component 22. Theflow control valve 520 is actuatable between at least first and secondpositions. As shown in FIG. 7, in the first position (e.g. closedposition) the flow control valve 520 closes the bypass outlet 506 anddefines a first fluid pathway extending from the inlet 504 through theaftertreatment component 22 to the aftertreatment outlet 508. In otherwords, when the flow control valve 520 is in the closed position,exhaust gasses, indicated by the directional arrow at 532, flow throughinto the inlet side of the housing and into the aftertreatment component22.

In contrast, as shown in FIG. 8, in the second position (e.g. openposition) the flow control valve 520 opens a bypass exhaust pipe 550that is downstream of the aftertreatment component 22 and defines asecond fluid pathway extending from the inlet side 512 of the housing502, past the aftertreatment component 22, through the flow controlvalve 520 and into bypass exhaust pipe 550. In other words, in the openposition the flow control valve 520 fluidly couples the inlet side 512of the housing 502 with the bypass exhaust pipe 550 such that exhaustgas, indicated by directional arrow 534, flows through the housing 302without flowing through the aftertreatment component 22.

While the aftertreatment component 22 is not closed off by the flowcontrol valve 520 when the flow control valve is in the second position,back pressure from the aftertreatment component 22 is higher in thebypass exhaust pipe 550 than in the aftertreatment component 22.Consequently, exhaust gasses will tend to flow through the flow controlvalve 550 and into the bypass exhaust pipe 550 instead of theaftertreatment component 22 since the exhaust bypass pipe 550 is thepath of least resistance for the exhaust gasses. Thus, the second fluidpathway effectively bypasses the aftertreatment component 22 when theflow control valve 520 is in the second position.

The bypass system 500 also includes the controller 130 described aboveand shown in detail in FIG. 4. The controller 130 is electronicallycoupled to the flow control valve 520 to control movement of the flowcontrol valve 520 between the first position and the second position. Inthe embodiment shown in FIGS. 7 and 8, the controller 130 sends a signalto the actuator 124 to move the flow control valve 520 to the desiredposition.

Referring to FIG. 9, a method for protecting an exhaust aftertreatmentsystem of an internal combustion engine, indicated generally at 700, isshown in accordance with another embodiment of the present invention.The method for protecting the exhaust aftertreatment system 700selectively diverts exhaust gasses from the engine away from anaftertreatment component, such as a Selective Catalyst Reducer,susceptible to deterioration from potentially harmful operational andenvironmental conditions which an internal combustion engine mayencounter. The method includes assessing a status of an operatingcondition associated with a physical condition of the aftertreatmentcomponent of the internal combustion engine, as shown at 702. The statusof the operating condition is compared with a threshold value thatcorresponds with deterioration of the physical condition of theaftertreatment component, shown at 704. If the operating conditionexceeds the threshold such that deterioration of the physical conditionof the aftertreatment component may occur, then a valve upstream of theaftertreatment component is moved to a first position to open a bypassfluid path that directs exhaust gasses around the component to reducedeterioration of the component, shown at 706. If the operating conditiondoes not exceed the threshold, then the valve is moved to a secondposition to close the bypass fluid path thereby directing exhaust gassesto the aftertreatment component, shown at 708.

In one aspect, the operating condition is a temperature of the exhaustgasses which is compared to a lower temperature threshold below which anunacceptable amount of unburned hydrocarbons remains in the exhaustgasses. In another aspect, the operating condition is a flow rate ofunburned hydrocarbons in the exhaust gasses which is compared to anupper threshold of an unacceptable amount of unburned hydrocarbons inthe exhaust gasses. In yet another aspect, the operating is atemperature of the exhaust gasses which is compared to a highertemperature threshold of the exhaust gasses above which the SelectiveCatalyst Reducer component produces harmful byproducts, such aspentoxides from a vanadia based catalyst, or may otherwise be rendereduseless by overheating. In yet another aspect, the operating conditionis a chemical formulation of the fuel used by the internal combustionengine which is compared to an upper threshold limit of sulfur contentabove which the sulfur deteriorates the aftertreatment component. In yetanother aspect, the operational condition is a geographical location ofthe internal combustion engine which is compared to geographicallocations that do not require emissions controls for internal combustionengines.

If the operating condition exceeds the threshold such that deteriorationof the physical condition of the aftertreatment component may occur,then a valve upstream of the aftertreatment component is moved to afirst position to open a bypass fluid path that directs exhaust gassesaround the component to reduce deterioration of the component. If theoperating condition does not exceed the threshold, then the valve ismoved to a second position to close the bypass fluid path therebydirecting exhaust gasses to the aftertreatment component.

The step of moving a valve to a first position includes receiving asignal from a controller that directs an actuator associated with thevalve to move the valve to the first position. Similarly, the step ofmoving the valve to the second position 716 includes receiving a signalfrom the controller directing the actuator to move the valve to thesecond position.

The step of moving the valve to the first position based on thethreshold comparison can be overridden by manually moving the valve tothe second position to close the first fluid path and open the secondfluid path to bypass the exhaust aftertreatment device.

In the above description, certain terms may be used such as “up,”“down,” “upper,” “lower,” “horizontal,” “vertical,” “left,” “right,” andthe like. These terms are used, where applicable, to provide someclarity of description when dealing with relative relationships. But,these terms are not intended to imply absolute relationships, positions,and/or orientations. For example, with respect to an object, an “upper”surface can become a “lower” surface simply by turning the object over.Nevertheless, it is still the same object.

Additionally, instances in this specification where one element is“coupled” to another element can include direct and indirect coupling.Direct coupling can be defined as one element coupled to and in somecontact with another element. Indirect coupling can be defined ascoupling between two elements not in direct contact with each other, buthaving one or more additional elements between the coupled elements.Further, as used herein, securing one element to another element caninclude direct securing and indirect securing. Additionally, as usedherein, “adjacent” does not necessarily denote contact. For example, oneelement can be adjacent another element without being in contact withthat element.

Reference throughout this specification to features, advantages, orsimilar language does not imply that all of the features and advantagesthat may be realized with the subject matter of the present disclosureshould be or are in any single embodiment or implementation of thesubject matter. Rather, language referring to the features andadvantages is understood to mean that a specific feature, advantage, orcharacteristic described in connection with an embodiment is included inat least one embodiment of the subject matter of the present disclosure.Discussion of the features and advantages, and similar language,throughout this specification may, but do not necessarily, refer to thesame embodiment or implementation.

The present subject matter may be embodied in other specific formswithout departing from its spirit or essential characteristics. Thedescribed embodiments are to be considered in all respects only asillustrative and not restrictive. The scope of the invention is,therefore, indicated by the appended claims rather than by the foregoingdescription. All changes which come within the meaning and range ofequivalency of the claims are to be embraced within their scope.

What is claimed is:
 1. A method for protecting an exhaust aftertreatmentsystem of an internal combustion engine from deterioration byselectively diverting exhaust gasses from the engine away from acomponent of the exhaust aftertreatment system, comprising: assessing astatus of an operating condition associated with a physical condition ofthe component of the internal combustion engine; comparing the status ofthe operating condition with a threshold value that corresponds withdeterioration of the physical condition of the component; moving a valveupstream of the component to a first position to open a bypass fluidpath directing exhaust gasses around the component when the status ofthe operating condition meets the threshold value to reducedeterioration of the component; and moving the valve to a secondposition to close the bypass fluid path thereby directing exhaust gassesto the component when the status of the operating condition does notmeet the threshold value.
 2. The method of claim 1, wherein theoperating condition includes a temperature of the exhaust gasses and thethreshold value is an upper temperature limit above which the componentproduces harmful byproducts.
 3. The method of claim 1, wherein theoperating condition includes a geographical location of the internalcombustion engine and the threshold value includes geographicallocations that do not require emissions controls for internal combustionengines.
 4. The method of claim 1, wherein the operating conditionincludes a chemical formulation of fuel used by the internal combustionengine and the threshold value includes chemicals that deteriorate thecomponent.
 5. The method of claim 4, wherein the chemicals thatdeteriorate the component include sulfur.
 6. The method of claim 1,further comprising: overriding the step of moving the valve to the firstposition based on the threshold comparison by manually moving the valveto the second position to close the first fluid path and open the secondfluid path to bypass the exhaust aftertreatment device.
 7. The method ofclaim 1, wherein the component is selected from the group consisting of:a selective catalytic reducer (SCR), an SCR coated filter, a dieseloxidation catalyst (DOC), a diesel particulate filter (DPF), andcombinations thereof.
 8. A method for protecting an exhaustaftertreatment system of an internal combustion engine fromdeterioration by selectively diverting exhaust gasses from the engineaway from a selective catalyst reducer (SCR) component of the exhaustaftertreatment system, comprising: assessing a status of an operatingcondition associated with a physical condition of the SCR component ofthe internal combustion engine; comparing the status of the operatingcondition with a threshold value that corresponds with deterioration ofthe physical condition of the SCR component, the operation condition andthreshold value including at least one of: a temperature of the exhaustgasses compared to a higher temperature threshold of the exhaust gassesabove which the SCR component produces harmful byproducts, fuelchemistry compared to an upper threshold limit of sulfur content abovewhich the sulfur deteriorates the SCR component, or a geographicalposition of the internal combustion engine compared to geographicallocations that do not require emissions controls for internal combustionengines; moving a valve upstream of the component to a first position toopen a bypass fluid path directing exhaust gasses around the componentwhen the status of the operating condition meets the threshold value toreduce deterioration of the SCR component; and moving the valve to asecond position to close the bypass fluid path thereby directing exhaustgasses to the SCR component when the status of the operating conditiondoes not meet the threshold value.
 9. An apparatus for bypassing anexhaust aftertreatment device of an internal combustion engine toprotect a selective catalytic reducer (SCR) component of the exhaustaftertreatment device from deterioration, the apparatus comprising: aflow control valve operable to open and close a bypass fluid pathwherein exhaust gasses from the engine bypass the exhaust aftertreatment device when the valve is in the open position and the exhaustgasses flow through the exhaust aftertreatment device when the valve isin the closed position; a sampling module that samples an operatingcondition of the internal combustion engine that is associated with aphysical condition of the SCR component; a comparison module thatcompares the operating condition with a threshold value that correspondswith deterioration of the physical condition of the SCR component; and acontrol module that operates the flow control valve to open the bypassfluid path if the operating condition does not meet the thresholdcondition and to close the bypass fluid path if the operating conditionmeets the threshold condition.
 10. The apparatus of claim 9, wherein thesampling module samples a temperature of the exhaust gasses and thecomparison module compares the temperature of the exhaust gasses to anupper temperature limit above which the SCR component produces harmfuloxidation byproducts.
 11. The apparatus of claim 9, wherein the samplingmodule samples a geographical location of the internal combustion engineand the threshold value includes geographical locations that do notrequire emissions controls for internal combustion engines.
 12. Theapparatus of claim 9, wherein the sampling module samples a chemicalformulation of fuel used by the internal combustion engine and thethreshold value includes chemicals that deteriorate the component. 13.The apparatus of claim 12, wherein the chemicals that deteriorate thecomponent include sulfur.
 14. The apparatus of claim 9, furthercomprising: a user interface associated with the control moduleconfigured to accept user input to override the control module controlof the flow control valve and manually open the valve to the bypassfluid path to bypass the exhaust aftertreatment device.
 15. An internalcombustion engine system, comprising: an internal combustion engine; anexhaust aftertreatment system including a selective catalyst reducer(SCR) component in exhaust receiving communication with the internalcombustion engine; and a bypass system operatively associated with theexhaust aftertreatment system operable to bypass the SCR component whenan operating condition of the internal combustion engine thatcorresponds with deterioration of a physical condition of the SCRcomponent is detected.
 16. The system of claim 15, the bypass systemfurther comprising: a flow control valve operable to open and close abypass fluid path wherein exhaust gasses from the engine bypass theexhaust after treatment device when the valve is in the open positionand the exhaust gasses flow through the exhaust aftertreatment devicewhen the valve is in the closed position; and a controller thatdetermines whether the flow control valve is open to the bypass fluidpath by sampling the operating condition of the internal combustionengine that is associated with the physical condition of the SCRcomponent and comparing the sample of the operating condition with athreshold value that corresponds with deterioration of the physicalcondition of the SCR component.
 17. The system of claim 16, wherein theoperating condition and threshold value include at least one of: atemperature of the exhaust gasses compared to a higher temperaturethreshold of the exhaust gasses above which the SCR component producesharmful byproducts; fuel chemistry compared to an upper threshold limitof sulfur content above which the sulfur deteriorates the SCR; or ageographical position of the internal combustion engine compared togeographical locations that do not require emissions controls forinternal combustion engines.